Copy prevention method and apparatus of a digital recording/reproducing system

ABSTRACT

A copy prevention method and apparatus of a digital magnetic recording/reproducing system performs the copy prevention function by encoding to insert a marker involving copy prevention function information and executing the function and allows a program supplier to realize a desired copy prevention function of various patterns, in which the marker formed by a control word for scrambling audio and video bit straps and copy prevention information for preventing an illegal copy is encrypted by an encoded key to be multiplexed with the audio and video bit strips scrambled by the control word. The marker transmitted is detected from the bit strips to be decrypted and analyzed by the encoded key to determine whether the copy is permitted or not, so that the detected marker is updated to be recorded on a video tape and the control word is produced from the marker to perform the descrambling to supply the result to a monitor to be displayed. Thus, the program supplier selects the copy prevention function, and a separate format converting apparatus is not required since a field defined within a GA format is utilized while an existing DVCR is not need to be changed for performing the copy prevention function as the data amount to be recorded is not increased.A method and apparatus for transmitting digital data are discussed. According to an embodiment, the invention is directed to a method of transmitting digital data using a data processing apparatus including a scrambler, the method comprising: scrambling, by the scrambler, one or more data units included in the digital data based on control data, the digital data including a first data block and one or more succeeding data blocks, each data block including a header and one data unit, at least the header in the first data block including the control data, wherein the first data block and the one or more succeeding data blocks are scrambled based on the control data included in the first data block; and transmitting, by the data processing apparatus, the one or more scrambled data units and the control data, the control data being used for controlling a parameter of a scrambling/descrambling operation.

This reissue application is a Continuation Application of Reissueapplication Ser. No. 09/592,148 (now abandoned) filed Jun. 12, 2000,which is a Continuation of Reissue application Ser. No. 09/094,575 filedJun. 12, 1998 (now Pat. No. Re. 37,052), which is a Reissue of U.S. Pat.No. 5,689,559, issued on Nov. 18, 1997 (U.S. application Ser. No.08/566,000), all these applications are incorporated by reference. Thepresent application also claims priority of Application No. 33336/1994filed in Republic of Korea on Dec. 8, 1994 under 35 U.S.C. §119. Note:More than one reissue application has been filed for the reissue of U.S.Pat. No. 5,689,559. The reissue applications are application Ser. No.09/097,162 (Now Pat. No. Re. 36,919) filed Jun. 12, 1998, Ser. No.09/094,575 (now Pat. No. Re. 37,052) filed Jun. 12, 1998, and Ser. No.09/592,148 (now abandoned) filed Jun. 12, 2000; as well as Ser. No.11/826,679 (now abandoned) filed Jul. 17, 2007, Ser. No. 11/826,680filed Jul. 17, 2007, Ser. No. 11/826,681 (now abandoned) filed Jul. 17,2007, Ser. No. 11/826,682 filed Jul. 17, 2007, Ser. No. 11/902,930 (nowabandoned) filed Sep. 26, 2007, Ser. No. 12/179,432 (now abandoned)filed Jul. 24, 2008, Ser. No. 12/179,443 (now abandoned) filed Jul. 24,2008, Ser. No. 12/179,453 (now abandoned) filed Jul. 24, 2008, Ser. No.12/184,152 (now abandoned) filed Jul. 31, 2008, and Ser. No. 12/621,430(now abandoned) filed Nov. 18, 2009, all of which are continuations ofSer. No. 09/592,148; and Ser. No. 12/318,742 filed Jan. 7, 2009, Ser.No. 12/318,743 (now abandoned) filed Jan. 7, 2009, Ser. No. 12/318,744(now abandoned) filed Jan. 7, 2009, Ser. No. 12/318,745 (presentapplication) filed Jan. 7, 2009, and Ser. No. 12/318,746 filed Jan. 7,2009, all of which are divisionals of Ser. No. 09/592,148; and Ser. No.12/641,258 (now abandoned) filed Dec. 17, 2009, Ser. No. 12/641,273 (nowabandoned) filed Dec. 17, 2009, and Ser. No. 12/641,266 (now abandoned)filed Dec. 17, 2009, all of which are continuations of Ser. No.11/826,681, which is a continuation of Ser. No. 09/592,148.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a copy prevention method and apparatusof a digital magnetic recording/reproducing system, and moreparticularly to a copy prevention method and apparatus of a digitalmagnetic recording/reproducing system, wherein a marker involving copyprevention function information and executing the function is coded andinserted to perform the copy prevention function and realize the copyprevention function of various patterns desired by a program supplierincludes control data for descrambling digital data.

2. Description of the Prior Art

One example of a conventional copy prevention method is described inU.S. Pat. No. 4,819,098, in which a signal inducing an interference toan automatic gain controller (AGC) circuit within a VCR is inserted to avideo waveform to be recorded on a tape. When the tape is reproduced todisplay the signal on a television, the interference signal does notaffect the AGC circuit of the television to allow, allowing for a normaldisplay.

However, when the reproduced signal is recorded by another VCR, i.e.,when it is duplicated, the interference signal brings about theinterference in the AGC circuit of the recording VCR to record incausing an inaccurate signal level to be recorded. Accordingly, thenodal display cannot be attained when reproducing a duplicated tape.

As another example, U.S. Pat. No. 4,571,642 utilizes a control trackemployed during performing the reproduction for synchronizing a servocircuit within a VCR, thereby for embodying the copy preventionfunction. The basic concept of this patent is for altering a videosignal to force the control track to be inaccurately recorded when thevideo signal is duplicated onto another tape.

Still another example is disclosed in U.S. Pat. No. 4,577,216, in whicha phase noise or the like is inserted to in a chroma burst portion of avideo signal to thereby embody the copy prevention function.

The above-mentioned methods are for using use a difference of betweenthe sensitivity between of circuits of in a television and of a VCR.Thus, the copy prepared to prevent the copy thereof as above may notexert the copy prevention function in a certain VCR, but may not executea normal display on a certain television.

The above copy prevention methods are of an analog system, which areavailable for preventing the copy of an NTSC-class video signal to ananalog VCR. However, in case of a high-definition image of the analogtelevision (ATV), the copy is performed by means of a digital VCR ratherthan an analog VCR, so that it is difficult to employ the copyprevention method of the analog system.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to provide a copyprevention method and apparatus of a digital magneticrecording/reproducing system applicable to a digital VCR andincorporated with various copy prevention functions to enable theselection of a copy prevention function desired by a program supplier.

To achieve the above object of the present invention, there is provideda copy prevention method of a digital magnetic recording/reproducingsystem, which is performed by an audio and video signal transmittingprocess and an audio and video signal receiving/recording process. Theaudio and video signal transmitted process is carried out in thesequence of encrypting a marker formed by a control word for scramblingaudio and video bit strips and copy prevention information forpreventing an illegal copy by means of an encoding key, and multiplexingthe marker with the audio and video bit strips scrambled by the controlword. Then, the audio and video signal receiving/recording process isperformed in the sequence of detecting the marker from the transmittedbit strips, decrypting and analyzing the detected marker by means of anencoded key to determine whether copy is permitted or not, updating thedetected marker to be recorded on a video tape, and generating thecontrol word from the marker to perform a descrambling and supply theaudio and video signals to be displayed on a monitor.

Also, a copy prevention apparatus of a digital magneticrecording/reproducing system includes a marker detecting and insertingpart for detecting a marker from input bit strips, and inserting theupdated marker to the bit strips to output the result. A markeranalyzing and processing part decrypts and analyzes the encrypted markerfrom the marker detecting and inserting part by means of an encoded key,outputs a control word for descrambling the bit strips, and updates andencrypting the decrypted marker by means of the encoded key to outputthe result. In addition, a buffer part buffers the control word andupdated and encrypted marker from the marker analyzing and processingsection, and inserts the updated and encrypted marker in the markerdetecting and inserting part, and a descrambler descrambles the bitstrips provided via the marker detecting and inserting part by means ofthe control word from the buffer part.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects and other advantages of the present invention willbecome more apparent by describing in detail preferred embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is a flow chart illustrating an audio and video signaltransmitting process in a copy prevention method according to thepresent invention;

FIG. 2 is a flow chart illustrating an audio and video signal receivingand recording process in the copy prevention method according to thepresent invention;

FIG. 3 is a view showing a structure of transport bit strips accordingto the present invention;

FIG. 4 is a block diagram showing a schematic construction of a copyprevention apparatus according to the present invention;

FIG. 5 is a block diagram showing a detailed construction of FIG. 4; and

FIGS. 6A to 6F are signal waveforms of respective parts shown in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A copy prevention method and apparatus of a digital magneticrecording/reproducing system according to the present inventionemphasizes a fact that a DVCR can record all diverse signals on a videotape, so that a variety of input signals are largely classified intotwo, and different use a copy prevention methods are performed for eachsignal method based on the type of input signal.

First, signals transmitted from a terrestrial broadcasting system, asatellite broadcasting system and a pay television broadcasting systemare classified as a broadcasting signal signals, and the following threecopy prevention functions are applicable when recording the abroadcasting signal.

ThreeThe three copy prevention functions are a no recording onto a videotapepermitted, a free record/copy onto the tape, and a singlegenerational recording onto the tape with no copy of the recorded tape.

Here, the third copy prevention function of the single generationalrecording onto the video tape with no duplication of the recorded tapeis for enabling the signal from a television receiver to record on thetape be recorded once but inhibiting the re-recording of the signal bymeans of another, for example, a DVCR is prohibited while thefirstly-recorded tape signal can be reproduced to watch through amonitor.

A second classification is for, for example, a rental tape to beidentified by a pretaped signal. Here, the copy prevention function ofthe pretaped signal is similar to the above no recording onto the tapeand the free record/copy onto the tape copy protection function, whichand has the following three copy protection functions.

The three functions are no copy onto another tape, free copy to anothertape and a single generational copy to another tape.

The single generational copy function to the other tape is of the copyprevention function for allowing a allows duplication from the originalrental tape, but inhibiting inhibits another copy from the duplication,which is utilized in a digital audio tape (DAT) duplicate.

The present invention is advantageous in that a program supplier selectsthe above functions when providing a program. For this purpose, theprogram supplier inserts desired copy prevention function information,i.e., a marker, into a predetermined field within the program.

The marker inserted to transport data by the program supplier prior tobeing transmitted is encoded, and, in order to impede an illegal copy,an encoding key for interpreting the marker is transferred via aseparate transmission line such as telephone line by a prescribed periodinterval, e.g., once a month, to be stored within a copy preventionapparatus.

In a system having an ATV decoder incorporated in a body with, forexample, the DVCR in a body, a copy prevention apparatus for embodyingthe copy prevention functions executes a digital copy preventionfunction during an interface process between the ATV decoder and theDVCR, and. The copy prevention apparatus decodes and determines themarker of a received program by means of a received encoded encoding keyto perform another function in accordance with respective copyprevention functions.

The copy prevention method of the digital magnetic recording/reproducingsystem according to the present invention is performed through an audioand video signal transmitting process as shown in FIG. 1, and an audioand video signal receiving and recording process as shown in FIG. 2.

The audio and video signal transmitting process is for encrypting themarker formed by a control word for scrambling audio and video bitstrips and copy prevention (hereinafter simply referred to as “CP”)information for preventing an illegal duplication by means of an encodedkey to multiplex and transmit the audio and video bit strips scrambledby the control word. Here, the marker is already formed by a programproducer to be multiplexed and transmitted together with the audio andvideo bit strips.

In more detail, as shown in FIG. 1, the audio and video signaltransmitting process is carried out in the sequence of an audio/videobitstrip encoding step 1 for encoding the audio and video bit strips, acontrol word generating step 2 for generating the control word forscrambling, and a scrambling step 6 for scrambling the encoded audio andvideo bit strips by means of the generated control word. Successively, aCP information generating step 3 generates the CP information forpreventing the illegal copy, and marker producing and encrypting. steps4 and 5 generates respectively generate the marker by using thegenerated control word and CP information and encrypts encrypt theresulting marker by means of the encoded an encoding key. Finally, amultiplexing and transmitting step 7 multiplexes the scrambled audio andvideo bit strips and encrypted marker to transmit the result.

The audio and video signal receiving and recording process is performedin such a manner that the marker is detected from the transmitted bitstrips and is decrypted by means of the encoded encoding key andanalyzed. Thus, it is determined whether the copy is permitted or not toupdate the detected marker to be recorded on a video tape, the detectedmarker is updated accordingly, and the control word is produced from themarker to carry out the descrambling and display the signals on amonitor. As a result, in which the audio and video signals transmittedfrom the program producer are recorded or displayed in accordance withthe marker.

More specifically, as shown inFIG. 2,shows the audio and video signalreceiving and recording process is performed byin detail. As shown, theprocess includes marker detecting steps 11 and 12 for detecting themarker by demultiplexing the transmitted bit strips, and decrypting themarker by means of the encoded encoding key, and a marker analyzing step13 for analyzing the detected marker to determine whether the a copy ispermitted or not and for detecting the control word. Then, thetransmitted audio and video bit strips are descrambled and decoded byusing the detected control word to supply the audio and video signals inaudio and video decoding steps 14 and 15. Thereafter, the detectedmarker is updated and encrypted by means of the encoded encoding key tobe inserted in case of permitting the copy after analyzing the marker ina and reinserted in the transmitted audio and video bit strips in markerinserting steps 16, 17 and 18 if copying is permitted.

The above-stated process will be described in detail below.

To begin with, the program producer encodes the audio and video bitstrips 1, generates the control word for scrambling 2, and scrambles theencoded audio and video bit strips by means of the generated controlword 6.

Also, the CP information for preventing the illegal copy is generated 3,and the marker is generated by using the generated control word and CPinformation 4, and the coded key is utilized to perform the encryption5.

Finally, the scrambled audio and video bit strips and encrypted markerare multiplexed 7 to be transmitted for the program recording orreproduction.

The transmitted bit strips are demultiplexed to detect the marker 11,and the encoded. The encoding key is utilized to perform the decryptionand the decrypted marker is output 12. The detected and decrypted markeris analyzed to determine whether the copy is permitted or not and thecontrol word is detected 13.

The detected control word is used for descrambling and decoding thetransmitted audio and video bit strips to provide the audio and videosignals to the monitor to be displayed for display 14 and 15.

In addition, when it is determined that the a copy is permitted afteranalyzing the marker, the detected marker is updated to be encrypted,re-encrypted by means of the encoded encoding key, and the result isinserted to the audio and video bit strips to be recorded 16, 17 and 18.

Here, a position of inserting the marker will be observed with referenceto FIG. 3.

The transmitted bit strips consists consist of transport packets of afixed length, i.e., 188 bytes, in which a transport header is displacedon the preceding stage of the bit strips. The transport header isdivided into a field of a fixed length of 4 bytes and an adaptationfield of a variable length. Then, a transport-private-data field existsas one field within the adaption field. The transport-private-data fieldconsists of an ID field and the encrypted marker. The ID field functionsas a an identifier for informing that the transport-private-data fieldis a field utilized for the copy prevention method according to thepresent invention, and the encrypted marker following the ID fieldembodies the copy prevention function of the present invention.

When the marker is decrypted by means of the encoded encoding key, thedecrypted marker is divided into a CP information area recorded withincluding the CP information for preventing the illegal copy, a controlword area recorded with including the control word CW for descrambling,and a reserved area.

That is, the decrypted marker is formed of 8 bytes consisting of the CPinformation area of one byte, the reserved area of three bytes andcontrol word area of four bytes.

At this time, the CP information is formatted by including agenerational copy control field which restricts the number of permittingthe copy permitted copies of the program, which. The generational copycontrol field is formed of an allowable generational field for limitingthe copy number of the program and a current generational fieldrepresenting a current generation of the duplicated program.

Next, the marker analyzing step 13 of the audio and video receiving andrecording process will be described in detail.

The marker analyzing step 13 is carried out by the CP informationdetecting step of detecting the CP information for preventing theillegal copy from the detected marker, a copy number limiting step ofcomparing the allowable generation of the allowable generational fieldfor restricting the number of permitting the copy of the program and thecurrent generation of the current generational field representing thecurrent generation of the duplicated program within the detected CPinformation to determine whether the copy is permitted or not, and thecontrol word detecting step of detecting the control word from thedetected marker for executing the descrambling.

In other words, the CP information for preventing the an illegal copy isdetected from the detected marker, and the allowable generation of theallowable generational field for limiting the copy number of the programis compared with the current generation of the current generationalfield representing the current generation of the duplicated programwithin the detected CP information to determine whether the copy ispermitted or not, so that the program is recorded in case of permittingthe copy, otherwise the. Otherwise, reproduction cannot be executed incase of inhibiting the copy, even though the recording is attained.

Next, the control word for descrambling is detected from the detectedmarker.

Here, the step of limiting the copy number is carried out by comparingthe allowable generation of the allowable generational field with thecurrent generation of the current generational field to determinewhether the allowable generation is the current generation, inhibitingthe copy when it is determined that the allowable generation is belowthe current generation, and permitting the copy when it is determinedthat the allowable generation is not below the current generation toproceed to the marker insertion step.

The copy number limiting step will be described below.

When the allowable generation is below the current generation aftercomparing the allowable generation of the allowable generational fieldpreset by the program producer with the current generation of thecurrent generational field representing the current copy number, thecopy number exceeds the copy number preset by the program producer.Thus, the copy cannot be further copying cannot be permitted.

At this time, in order to inhibit the copy, the control word isdestructed or is not output to block the, which blocks reproductionafter performing of the copy. This is because the audio and video bitstrips are recorded under the state of being scrambled, the scrambledaudio and video bit strips cannot be descrambled without the controlword.

Therefore, by destructing the control word, the reproduction and displaycannot be achieved even though the audio and video bit strips arerecorded to; thereby have having the same effect of as impeding therecording of them.

At this time, since the control word is periodically changed in the ofan interval of 0.6 second, the reproduction is impeded by destructingthe succeeding control word even after accomplishing the recording.

Also, a control track within the video tape may be destructed to inhibitthe copy when the recording medium is a video tape.

On the other hand, the marker is positioned on the private data fieldwithin the bit strips whenever the control word is changed.

Here, since the control word is periodically changed, the markerincluding the control word is received whenever the control word ischanged to be supplied.

Meantime, the marker inserting step is performed by updating the markerwhen the copy is permitted after analyzing the marker 16, encrypting theupdated marker by means of the encoded key 17, and replacing theencrypted marker with the following marker to be inserted 18.

In other words, if the copy is permitted after analyzing the marker, thecurrent generation of the current generational field is augmented by oneto update the marker 16. That is, the CP information including theupdated current generational field obtained by augmenting the currentgeneration by one is summed with the control word to be the updatedmarker.

The updated marker is encrypted by means of the encoded key to bereplaced with encoding key and is inserted to replace the succeedingmarker and inserted 17. More specifically, as the marker is suppliedwhenever the control word is changed, it is inserted whenever thecontrol word is changed.

In other word words, as shown in FIG. 3, the detection of the encryptedmarker and the replacement of the updated marker should be accomplishedaltogether on time basis.

Meanwhile, the encoded encoding key for encrypting and decrypting themarker is transmitted via a separate transmission line in apredetermined time interval and is stored to be utilized, therebyperfectly preventing the illegal copy.

That is, the marker encrypted by the encoded encoding key is transmittedand recorded together with the bit strips. Here, the control word fordescrambling the scrambled audio and video bit strips is included in themarker, so that the marker should be primarily decrypted to obtain thecontrol word. However, since the encoded encoding key for decrypting themarker is periodically changed, it is impossible to decrypt the markerwithout the encoded encoding key. Accordingly, it is further difficultto illegally obtain the control word.

As shown in FIG. 4, the copy prevention apparatus of the digitalmagnetic recording/reproducing system according to the present inventionincludes a marker detecting/inserting section 21, a descrambler 24, amarker analyzing/processing section 22 and a buffer section 23.

Marker detecting/inserting section 21 detects the marker from thereceived bit strips, and inserts to output the updated marker, i.e., theupdated and encrypted marker, from buffer section 23 to the bit strips.

Marker analyzing/processing section 22 utilizes the encoded key encodingkeys to decrypt and analyze the encrypted marker from markerdetecting/inserting section 21, thereby providing the control word CWfor descrambling the bit strips. Then, the decrypted marker is updatedand encrypted by the encoded encoding key to be for output.

Buffer section 23 buffers control word CW and the updated and encryptedmarker IEM from marker analyzing/processing section 22, so that theupdated and encrypted marker IEM is supplied to be inserted in markerdetecting/inserting section 21.

Descrambler 24 descrambles the bit strips output via markerdetecting/inserting section 21 by means of the control word CW frombuffer section 23 to supply the result to the monitor to be displayed orto, for example, a DVCR to record the bit strips inserted with themarker.

Here, the encoded encoding key is transmitted via the separatetransmission line in at a predetermined time interval and is stored asthe copy prevention method of the digital magnetic recording/reproducingsystem according to the present invention to double a copyrightprotection effect.

Referring to FIG. 3, the structure of the transport bit strips andmarker will be described prior to describing the operation of the copyprevention apparatus of the digital magnetic recording/reproducingsystem constructed as above.

In the copy prevention apparatus of the digital magneticrecording/reproducing system, the marker is placed on thetransport-private-data field within the bit strips, and the CPinformation area recorded with the CP information for preventing theillegal copy and the control word area recorded with the control word CWfor descrambling are included thereto as shown in FIG. 3, like the copyprevention method.

Here, the CP information is formatted by including the generational copycontrol field for restricting the number of permitted copies of theprogram, which is formed of the allowable generational field forlimiting the copy number of the program and the current generationalfield representing the current generation of the duplicated program.

The marker is formed of 8 bytes consisting of the CP information area ofone byte and control word area of four bytes.

Hereinbelow, an operation of the copy prevention apparatus of thedigital magnetic recording/reproducing system according to the presentinvention will be briefly described with reference to FIG. 4.

First, a process of displaying the input bit strips on the monitor willbe described.

The input bit strips are supplied to marker analyzing/processing section22 under the state that the marker is detected and encrypted in markerdetecting/inserting section 21.

Encrypted marker EM is decrypted by means of the encoded encoding key tobe analyzed in marker analyzing/processing section 22. At this time, thecontrol word is detected from the analyzed marker to be buffered viabuffer section 23 for descrambling the bit strips and is supplied todescrambler 24.

The bit strips, after detecting the detection of the marker in markerdetecting/inserting section 21, are descrambled in descrambler 24 inaccordance with the control word from buffer section 23, and provided tothe monitor to be displayed for display.

Next, a process of recording the input bit strips via, for example, theDVCR will be described.

The process of detecting and analyzing the marker from the input bitstrips is executed in the same manner.

That is, the input bit strips is are supplied to markeranalyzing/processing section 22 under the state that the marker isdetected and encrypted decrypted in marker detecting/inserting section21.

Encrypted marker EM is decrypted by means of the encoded encoding key inmarker analyzing/processing section 22 to detect the control word. Atthis time, the recording can be performed or not in accordance with theresult of the analysis. If the recording is not permitted, the detectedcontrol word is destructed to impede the reproduction even though therecording can be attained. Otherwise, the current generation of thecurrent generational field within the marker is augmented by one toupdate the marker, so that the encoded encoding key is utilized toencrypt the marker to supply, and the result is supplied to buffersection 23.

The updated and encrypted marker is buffered in buffer section 23 and issupplied to marker detecting/inserting section 21 to be inserted to theinput bit strips.

Meantime, the control word is periodically changed in the interval of0.6 second, and the marker is placed on the transport-private-data fieldwithin the bit strips whenever the control word is changed.

Consequently, the updated and encrypted marker is replaced with replacesthe succeeding marker to be inserted.

The bit strips inserted with the updated and encrypted marker passthrough descrambler 24 intact and are output to be recorded in the DVCR.

The detailed construction and operation of the copy prevention apparatusin the digital magnetic recording/reproducing system formed as abovewill be described with reference to the accompanying drawings.

FIG. 5 is a detailed construction view showing the copy preventionapparatus of FIG. 4, which will be described below.

Marker detecting/inserting section 21 includes a marker detector 31which detects the encrypted marker from the input bit strips andsupplies the detected marker to marker analyzing/processing section 22and a marker detection flag signal for informing of the position of theencrypted marker within the bit strips to descrambler 24 to be. The flagis used as a reference signal of for initializing descrambler 24 whileoutputting the bit strips. In addition to marker detector 31, a markerinserter 32 inserts the updated and encrypted marker from buffer section23 to into the bit strips from marker detector 31 in accordance with themarker detection flag signal from marker detector 31 to output the. Theresult is output to descrambler 24.

Marker analyzing/processing section 22 has a marker decoder 34 fordecrypting the encrypted marker from marker detector 31 of markerdetecting/inserting section 21 by means of the encoded encoding key, anda marker analyzer 34 for analyzing analyzes the CP information withinthe marker from marker decoder 34 to output the control word to buffersection 23 when the copy is permitted while outputting a control signalfor updating the marker. Additionally, a marker updating/encoding unit35 updates the marker from marker decoder 34 in accordance with thecontrol signal from marker analyzer 34 to encrypt the marker by means ofthe encoded encoding key to output the result to buffer section 23.

Here, marker analyzing/processing section 22 further includes anencoding key storage unit (not shown) for storing the encoded encodingkey and to output the result encoding key to marker decoder 33 andmarker updating/encoding unit 35.

BesidesAlso, marker analyzer 34 compares the allowable generation of theallowable generational field for restricting the number of permittingthe copy of the program with the current generation of the currentgenerational field representing the current generation of the duplicatedprogram to determine whether the a copy is permitted or not.

Buffer section 23 includes a marker buffer 36 for temporally storing theupdated and encrypted marker from marker analyzing/processing section 22to supply it to marker detecting/inserting section 21, and a controlword buffer 37 for temporally storing the control word from markeranalyzing/processing section 22 to supply it to descrambler 24.

An operation of the copy prevention apparatus of the digital magneticrecording system according to the present invention constructed as abovewill be described with reference to FIG. 6 FIGS. 6A-6G.

FIG. 6A is a timing chart of the transmitted bit strips, FIG. 6B is ofillustrates the marker detection flag m-det-flag, FIG. 6C is ofillustrates the control word CW(i) from marker analyzer 34, FIG. 6D isof illustrates the updated and encrypted master IEM(i) from markerupdating/encoding unit 35, FIG. 6F is of illustrates the updated andencrypted marker IEM(i) from marker buffer 36, and FIG. 6G is ofillustrates the control word CW(i) from control word buffer 37.

Encrypted marker EM(i) is included in the transmitted bit strips.

The transmitted bit strips including encrypted marker EM(i) is areformed as shown in FIG. 6A, which is supplied to marker detector 31 todetect encrypted marker EM(i) to be supplied to marker decoder 33. Also,marker detector 31 generates marker detection flag signal m-det-flag forinforming of the position of the encrypted marker at the encryptedmarker EM(i) portion as shown in FIG. 6B, so that the generated signalis supplied to marker inserter 32 together with the bit strips includingencrypted marker EM(i). Also, marker detection flag m-det-flag issupplied to descrambler 24 to be utilized as the reference signal forinitializing descrambler 24 by control word CW(i−1) from control wordbuffer 37.

Encrypted marker EM(i) is decrypted by the encoding key in markerdecoder 33 to be and is supplied as decrypted marker M(i).

Decrypted marker M(i) is analyzed in marker analyzer 34 to determinewhether the copy is permitted or not. In other words, marker analyzer 34compares the CP information within decrypted marker M(i), i.e., theallowable generational field with the current generational field, anddetermines to permit the copy when the allowable generational field isnot below the current generational field.

When the copy is permitted as above, marker analyzer 34 slightly delayscontrol word CW(i), which is a part of decrypted marker M(i), to besupplied to control word buffer 37, as shown in FIG. 6C. At this time,marker analyzer 34 provide provides the control signal to markerupdating/encoding unit 35 to control the updating of the marker.

That is, marker decoder 33 form forms decrypted marker M(i) fromencrypted marker EM(i) after delaying a delay time required for thedecode, and the marker analyzer 34 generates control word CW(i) fromdecrypted marker M(i) in marker analyzer 34.

At this time, control word CW(i) is transmitted to control word buffer37 to be stored until it is utilized in descrambler 24.

Decrypted marker M(i) from marker decoder 33 is updated in accordancewith the control signal from marker analyzer 34 in markerupdating/encoding unit 35.

That is, the updated data is the data recorded on the currentgenerational field within the marker, which is obtained by adding one tothe previously recorded current generation.

The marker updated as described above is encrypted. i.e., encoded, inaccordance with the encoded encoding key to be supplied to marker buffer36 as shown in FIG. 6D, slightly delayed with respect to control wordCW(i) from marker analyzer 34 as shown in FIG. 6C. In more detail, theencrypted marker M(i) from marker decoder 33 is supplied to markerupdating/encoding unit 35 to be generated as marker IEM(i), which isupdated and encrypted after delaying the a delay time required for theencoding to be, and marker IEM(i) is supplied to marker buffer 36.

Here, the point of generating updated and encrypted marker IEM(i) andcontrol word CW(i) from marker updating/encoding unit 35 and markeranalyzer 34 does not coincide with a point of utilizing updated andencrypted marker IEM(i) and control word CW(i) in marker inserter 32 anddescrambler 24, i.e., the points of performing the replaceable insertionand initialization of descrambler 24 do not coincide with each other.Thus, updated and encrypted marker IEM(i) and control word CW(i) frommarker updating/encoding unit 35 and marker analyzer 34 are temporallystored in marker buffer 36 and control word buffer 37 for that time.

As shown in FIG. 6E, updated and encrypted marker IEM(i) temporallystored in marker buffer 36 and synchronized to be output is inserted bymarker inserter 32 to into the bit strips from marker detector 31.

In more detail, marker inserter 32 receives the bit strips havingencrypted marker EM(i) and marker detection flag signal m-det-flag frommarker detector 31, and receives updated and encrypted marker IEM(i)which will be replaceably inserted to into the position of encryptedmarker EM(i) from marker buffer 36, so that updated and encrypted markerIEM(i) is replacably inserted to the position of marker detection flagsignal m-det-flag in the transmitted bit strips including encryptedmarker-EM(i) as shown in FIG. 6E.

In other words, marker inserter 32 inserts updated and encrypted markerIEM(i) from marker buffer 37 replacing encrypted marker EM(i+1) at theposition of producing marker detection flag signal m-det-flag.

Here, the replacably inserted marker IEM(i) is formed from theimmediately detected preceding encrypted marker. Accordingly, as shownin FIG. 6E, the marker IEM(i) is stored in marker buffer 37 for acertain period to be and then provided to marker inserter 32.

As shown in FIG. 6F, control word CW(i−1) is temporally stored incontrol word buffer 37 to be synchronized prior to being output and isutilized for descrambling the transmitted bit strips from markerinserter 32 in descrambler 24.

At this time, descrambler 24 uses marker detection flag signalm-det-flag from marker detector 31 as the reference signal forinitializing based on control word CW(i−1) from control word buffer 37.

More specifically, descrambler 24 must be initialized by control wordCW(i−N) from control word buffer 37 during a period from the point ofgenerating encrypted marker EM(i), i.e., from a position of detectingmarker detecting flag signal m-det-flag to the point before startingpayload of a transport packet, where N is a natural number greater thanzero. Here, control word CW(i−N) is a control word formed from encryptedmarker EM(i−N) transmitted before encrypted marker EM(i) as many as Ntimes. The natural number ‘N’ allows for arbitrarily controlling theinitializing point of descrambler 24.

In the copy prevention method and apparatus of the digital magneticrecording/reproducing system according to the present invention asdescribed above, a program supplier can select the copy preventionfunction, and the field defined within a GA format is utilized. As theresult, a separate format transformation apparatus for the copyprevention function is not required, and there is no increase in dataamount to be recorded to perform the copy prevention function withoutconverting, for example, the general digital VCR.

While the present invention has been particularly shown and describedwith reference to particular embodiment thereof, it will be understoodby those skilled in the art that various changes in form and details maybe effected therein without departing from the spirit and scope of theinvention as defined by the appended claims.

What is claimed is:
 1. A copy prevention method of a digital magneticrecording/reproducing system comprising: an audio and video signaltransmitting process of encrypting a marker formed by a control word forscrambling audio and video bit strips and copy prevention informationfor preventing an illegal copy by means of an encoding key, andmultiplexing said marker with said audio and video bit strips scrambledby said control word, and an audio and video signal receiving/recordingprocess of detecting said marker from said transmitted bit strips,decrypting and analyzing the detected marker by means of an encoded keyto determine whether copy is permitted or not, updating said detectedmarker to be recorded on a video tape, and generating said control wordfrom said marker to perform a descrambling and supply the audio andvideo signals to be displayed on a monitor.
 2. A copy prevention methodof a digital magnetic recording/reproducing system as claimed in claim1, wherein said marker is placed on a transport-private-data fieldwithin said bit strips.
 3. A copy prevention method of a digitalmagnetic recording/reproducing system as claimed in claim 2, whereinsaid marker is comprised of a copy prevention information area recordedwith said copy prevention information for preventing said illegal copy,and a control word area recorded with said control word fordescrambling.
 4. A copy prevention method of a digital magneticrecording/reproducing system as claimed in claim 3, wherein said markeris formed of 8 bytes.
 5. A copy prevention method of a digital magneticrecording/reproducing system as claimed in claim 4, wherein said copyprevention area is formed of one byte.
 6. A copy prevention method of adigital magnetic recording/reproducing system as claimed in claim 4,wherein said control word area is formed of four bytes.
 7. A copyprevention method of a digital magnetic recording/reproducing system asclaimed in claim 3, wherein said copy prevention information isformatted by including a generational copy control field for restrictingthe number of permitting said copy of a program.
 8. A copy preventionmethod of a digital magnetic recording/reproducing system as claimed inclaim 7, wherein said generational copy control field comprises: anallowable generational field for restricting the copy number of saidprogram; and a current generational field representing a currentgeneration of a duplicated program.
 9. A copy prevention-method of adigital magnetic recording/reproducing system as claimed in claim 1,wherein said audio and video transmitting process comprises: an audioand video bit-strip encoding step of encoding said audio and video bitstrips; a control word generating step of generating said control wordfor scrambling; a scrambling step for scrambling said encoded audio andvideo bit strips by means of said generated control word; a copyprevention information generating step of generating said copyprevention information for preventing said illegal copy; a markergenerating and encrypting step of generating said marker by means ofsaid generated control word and copy prevention information andencrypting said marker by means of said encoded key; and a multiplexingand transmitting step of multiplexing to transmit said scrambled audioand video bit strips and encrypted marker.
 10. A copy prevention methodof a digital magnetic recording/reproducing system as claimed in claim1, wherein said audio and video signal receiving/recording processcomprises: a marker detecting step of demultiplexing said transmittedbit strips to detect said marker, and decrypting said marker by means ofsaid encoded key; a marker analyzing step of analyzing said detectedmarker to determine whether said copy is permitted or not, and detectingsaid control word; an audio and video decoding step of descrambling anddecoding said transmitted audio and video bit strips by means of saiddetected control word, and outputting said audio and video signals; anda marker inserting step of updating said detected marker and encryptingsaid updated marker by means of said encoded key to insert the resultwhen it is determined that said copy is permitted after analyzing saidmarker.
 11. A copy prevention method of a digital magneticrecording/reproducing system as claimed in claim 10, wherein said markeranalyzing step comprises: a copy prevention information detecting stepof detecting said copy prevention information for preventing saidillegal copy from said detected marker; a copy number restricting stepof comparing an allowable generation of said allowable generationalfield and a current generation of said current generational fieldrepresenting said current generation for restricting the number ofpermitting said copy of said program within said detected copyprevention information, and determining whether said copy is permittedor not-to process the result; and a control word detecting step ofdetecting said control word for descrambling from said detected marker.12. A copy prevention method of a digital magnetic recording/reproducingsystem as claimed in claim 11, wherein said copy number restricting stepcomprises: comparing said allowable generation of said allowablegenerational field with said current generation of said currentgenerational field to determine whether said allowable generation isbelow said current generation; inhibiting said copy when it isdetermined that said allowable generation is below said currentgeneration; and permitting said copy when it is determined that saidallowable generation is-not below said current generation, andproceeding to said marker inserting step.
 13. A copy prevention methodof a digital magnetic recording/reproducing system as claimed in claim12, wherein said step of inhibiting said copy is performed bydestructing said control word or impeding an output of said control wordto block a reproduction after recording.
 14. A copy prevention method ofa digital magnetic recording/reproducing system as claimed in claim 10,wherein said control word is periodically changed.
 15. A copy preventionmethod of a digital magnetic recording/reproducing system as claimed inclaim 14, wherein said control word is changed in the interval of 0.6second.
 16. A copy prevention method of a digital magneticrecording/reproducing system as claimed in claim 14, wherein said markeris placed on said transport-private-data field within said bit stripswhenever said control word is changed.
 17. A copy prevention method of adigital magnetic recording/reproducing system as claimed in claim 16,wherein said marker inserting step comprises the steps of: updating saidmarker when the analysis of said marker determines to permit said copy;encrypting said updated marker by means of said encoded key; andreplacably inserting said encrypted marker with a succeeding marker. 18.A copy prevention method of a digital magnetic recording/reproducingsystem as claimed in claim 1, wherein said encoded key is transportedvia a separate transmission line to be stored.
 19. A copy preventionmethod of a digital magnetic recording/reproducing system as claimed inclaim 18, wherein said encoded key is transported via said separatetransmission line for a prescribed time interval.
 20. A copy preventionapparatus of a digital magnetic recording/reproducing system comprising:an encrypted marker detecting and inserting part for detecting a markerfrom input bit strips, and inserting an updated marker to said bitstrips to output the result; a marker analyzing and processing part fordecrypting and analyzing the encrypted marker from said marker detectingand inserting part by means of an encoded key, outputting a control wordfor descrambling said bit strips, and updating and encrypting thedecrypted marker by means of said encoded key to output the result; abuffer part for buffering said control word and updated and encryptedmarker from said marker analyzing and processing part, and insertingsaid updated and encrypted marker in said marker detecting and insertingpart; and a descrambler for descrambling said bit strips provided viasaid marker detecting and inserting pant by means of said control wordfrom said buffer part.
 21. A copy prevention apparatus of a digitalmagnetic recording/reproducing system as claimed in claim 20, whereinsaid encoded key is transported via a separate transmission line to bestored.
 22. A copy prevention apparatus of a digital magneticrecording/reproducing system as claimed in claim 21, wherein saidencoded key is transported via said separate transmission line for aprescribed time interval.
 23. A copy prevention apparatus of a digitalmagnetic recording/reproducing system as claimed in claim 20, whereinsaid marker is placed on a transport-private-data field within said bitstrips whenever said control word is changed.
 24. A copy preventionapparatus of a digital magnetic recording/reproducing system as claimedin claim 23, wherein said marker is comprised of a copy preventioninformation area recorded with said copy prevention information forpreventing said illegal copy, and a control word area recorded with saidcontrol word for descrambling.
 25. A copy prevention apparatus of adigital magnetic recording/reproducing system as claimed in claim 24,wherein said marker is formed of 8 bytes.
 26. A copy preventionapparatus of a digital magnetic recording/reproducing system as claimedin claim 25, wherein said copy prevention area is formed of one byte.27. A copy prevention apparatus of a digital magneticrecording/reproducing system as claimed in claim 25, wherein saidcontrol word area is formed of four bytes.
 28. A copy preventionapparatus of a digital magnetic recording/reproducing system as claimedin claim 24, wherein said copy prevention information is formatted byincluding a generational copy control field for restricting the copynumber of a program.
 29. A copy prevention apparatus of a digitalmagnetic recording/reproducing system as claimed in claim 28, whereinsaid generational copy control field comprises: an allowablegenerational field for restricting the number of permitting the copy ofa program; and a current generational field representing a currentgeneration of a duplicated program.
 30. A copy prevention apparatus of adigital magnetic recording/reproducing system as claimed in claim 20,wherein said control word is periodically changed.
 31. A copy preventionapparatus of a digital magnetic recording/reproducing system as claimedin claim 30, wherein said control word is changed in the interval of 0.6second.
 32. A copy prevention apparatus of a digital magneticrecording/reproducing system as claimed in claim 30, wherein said markeris placed on a transport-private-data field within said bit stripswhenever said control word is changed.
 33. A copy prevention apparatusof a digital magnetic recording/reproducing system as claimed in claim30, wherein said marker detecting and inserting part replacably insertssaid updated marker with a succeeding marker.
 34. A copy preventionapparatus of a digital magnetic recording/reproducing system as claimedin claim 20, wherein said marker detecting and inserting part comprises:a marker detecting section for detecting to output said encrypted markerfrom said input bit strips to said marker analyzing and processing part,outputting a marker detection flag signal for informing of the positionof said encrypted marker within said bit strips to said descrambler tobe used as a reference signal of initializing said descrambler, andoutputting said bit strips; and a marker inserting section for insertingsaid updated and encrypted marker from said buffer part to said bitstrips from said marker detecting section in accordance with said markerdetection flag signal from said marker detecting section to output theresult to said descrambler.
 35. A copy prevention apparatus of a digitalmagnetic recording/reproducing system as claimed in claim 24, whereinsaid marker analyzing and processing part comprises: a marker decodingsection for decrypting said encrypted marker from said marker detectingand inserting part by means of said encoded key; a marker analyzingsection for analyzing said copy prevention information within saidmarker from said marker decoding section, and outputting said controlword to said buffer part and a control signal for updating said markerwhen said copy is permitted; and a marker updating and encoding sectionfor updating said marker from said marker decoding section in accordancewith said control signal from said marker analyzing section, andencrypting said updated marker by means of said encoded key to outputthe result to said buffer part.
 36. A copy prevention apparatus of adigital magnetic recording/reproducing system as claimed in claim 35,wherein said marker analyzing and processing part further comprises anencoded key storage section for storing said encoded key to output it tosaid marker analyzing section and marker updating and encoding section.37. A copy prevention apparatus of a digital magneticrecording/reproducing system as claimed in claim 35, wherein said markeranalyzing section compares an allowable generation of an allowablegenerational field with a current generation of a current generationalfield representing a current generation of a duplicated program todetermine whether said copy is permitted or not.
 38. A copy preventionapparatus of a digital magnetic recording/reproducing system as claimedin claim 20, wherein said buffer part comprises: a marker buffer fortemporally storing said updated and encrypted marker from said markeranalyzing and processing part, and outputting the result to said markerdetecting and inserting part; and a control word buffer for temporallystoring said control word from said marker analyzing and processingpart, and outputting the result to said descrambler.
 39. A method oftransmitting digital data using a data processing apparatus including ascrambler, the method comprising: generating control data forinitializing the scrambler; initializing the scrambler based on thecontrol data directly input into the scrambler; scrambling, using thesame initialized scrambler and the same control data, both digital audiodata and digital video data; generating a first 188 byte data blockincluding a header with the control data used to initialize thescrambler and a scrambled data portion including the scrambled digitalaudio and/or digital video data; generating at least a second 188 bytedata block including the scrambled digital audio and digital video dataand not including the control data; determining if a minimum of amultiple of four 188 byte data blocks have been scrambled; determiningif a timing point that includes a decimal fraction of 0.66 control wordsper second (CW/s) has passed since a previous initialization of thescrambler; re-initializing the scrambler based on a new control wordwhen the determining steps determine either the minimum of the multipleof four 188 byte data blocks have been scrambled or the timing pointthat includes the decimal fraction of 0.66 control words per second(CW/s) has passed since the previous initialization of the scrambler;and transmitting, by the data processing apparatus, the generated firstdata block and the at least second data block.
 40. The method of claim39, wherein the scrambling step does not scramble the header in thefirst 188 byte data block.
 41. The method of claim 43, furthercomprising identifying the number of times the digital data has beencopied and/or the number of times permitted to copy the digital data,based on copy prevention information included in the header of the firstdata block, wherein the copy prevention information includes at leastone of current generation information and allowable generationinformation, the current generation information indicating the number oftimes the digital data has been copied and the allowable generationinformation indicating the number of times permitted to copy the digitaldata.
 42. An apparatus for transmitting digital data, comprising: aprocessor; and a memory connected to the processor and includingexecutable instructions that when executed by the processor, cause theprocessor to perform: generating control data for initializing thescrambler; initializing the scrambler based on the control data;scrambling, using the same initialized scrambler and the same controldata, both digital audio data and digital video data; generating a first188 byte data block including a header with the control data used toinitialize the scrambler and a scrambled data portion including thescrambled digital audio and/or digital video data; generating at least asecond 188 byte data block including the scrambled digital audio anddigital video data and not including the control data; determining if aminimum of a multiple of four 188 byte data blocks have been scrambled;determining if a timing point that includes a decimal fraction of 0.66control words per second (CW/s) has passed since a previousinitialization of the scrambler; re-initializing the scrambler based ona new control word and based on the determination that either theminimum of the multiple of four 188 byte data blocks have been scrambledor the timing point that includes the decimal fraction of 0.66 controlwords per second (CW/s) has passed since the previous initialization ofthe scrambler; and transmitting the generated first 188 byte data blockand the at least second 188 byte data block.
 43. The apparatus of claim42, wherein the executable instructions further cause the processor toperform: not scrambling the header in the first 188 byte data block. 44.The apparatus of claim 42, wherein the executable instructions furthercause the processor to perform: identifying the number of times thedigital data has been copied and/or the number of times permitted tocopy the digital data, based on copy prevention information included inthe header of the first data block, the copy prevention informationincluding at least one of current generation information and allowablegeneration information, the current generation information indicatingthe number of times the digital data has been copied and the allowablegeneration information indicating the number of times permitted to copythe digital data.
 45. The apparatus of claim 42, wherein the executableinstructions further cause the processor to perform: determining whetherthe digital data requires a copy prevention function based onidentification information included in the header of the first datablock, the identification information indicating whether or not at leasta portion of the digital data has a data structure for copy prevention,and the controller is further configured to detect copy preventioninformation for controlling the copy prevention function from thedigital data according to a result of this determination.
 46. The methodof claim 39, further comprising: determining whether the digital datarequires a copy prevention function based on identification informationincluded in the header of the first data block, the identificationinformation indicating whether or not at least a portion of the digitaldata has a data structure for copy prevention; and detecting copyprevention information for controlling the copy prevention function fromthe digital data according to a result of this determining step.